Cillian Murphy had to have his head 'glued shut' at 3 a.m. on the 'Oppenheimer' set because of a pillow Emily Blunt gave him

• Cillian Murphy had to have his head "glued shut" on the set of "Oppenheimer."
• Emily Blunt gave him a luxury pillow to help him sleep during the intense production.

Cillian Murphy had to have his head glued shut by a makeup artist at 3 a.m. on the "Oppenheimer" set after he cut it open while sleeping on a pillow Emily Blunt gave him.

The Christopher Nolan movie follows scientist J. Robert Oppenheimer during World War II when he built the world's first atomic bomb. It also examines his complicated personal life, including the affair he had with Jean Tatlock (Florence Pugh) while being married to Kitty Puening (Emily Blunt).

Because of the intense nature of the film, Blunt gifted him a luxury pillow to help him sleep at night.

"I just felt Cillian needed, even more than food, was sleep on this movie. So I got him this very beautiful pillow that I'm obsessed with. These pillows, Hastens pillows. I gave him this pillow, but… do you mind if I tell the story?" Blunt said on Thursday's "Jimmy Kimmel Live!".

"He was really luxuriating in this pillow one night, and he woke up in the middle of the night, this is what he told me the next day," she recalled.

"And he went to fluff himself back down in the pillow, misjudged where it was, and smashed his head open on the bedside table. So he came to work, and they had to glue his head shut!"

Cillian said: "I was a bit shocked you know! I was having a great sleep, and I had this amazing pillow, strange bed, strange table, and bang."

He pointed out that the cast always got up in the early hours of the morning to start filming, so he went straight to Luisa Abel, the "Oppenheimer" makeup designer, for help.

"We were getting up at before it was bright, like at 2 a.m. or something, 3 a.m. So I called her then, and I just came in, and then she glued my head, and covered it all up, and you don't even see it in the movie, I think," Murphy explained.

The pillow isn't the first gift that Blunt gave to her "Oppenheimer" colleagues, as in January she recalled giving the director his own pair of Ugg boots.

Nolan hated the boots that Blunt wore on set, and she compared his reaction to seeing her in them to the infamous Miranda Priestly (Meryl Streep) monologue from "The Devil Wears Prada."